<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">
	
	var a = 10;
	var b = new Number(1);
	function show(a,b){
		arguments[0] = 5;
		arguments[1].b = a;
		alert(a);//5  -> 
		alert(b);//10 -> o  1

	}
	show(a,b);
	alert(a);//10 
	alert(b);//1 
	alert(a.b);//10->  蒙的 oundefined


</script>
</body>
</html>